Order doesn't matter for flow, a radiator will cause the same pressure drop for a given flow whether it is first or last. It makes more sense to pick an order that minimizes tubing length and number of fittings.
Your layout will work. Keep the 1/4 section as short as possible. If you can, make a custom 1-to-3 splitter to substitute for the first two wyes.
You made such a nice diagram, I couldn't resist.
